Mercedes is accused of fitting millions of its diesel vehicles with “defeat devices” worldwide. These devices were designed to reduce emissions levels in a regulatory test environment. Without passing these tests, the cars would not have been cleared to drive on UK roads. Lawyers argue Mercedes therefore sold cars that were far more polluting than drivers were told (and more polluting than legally allowed), impacting the re-sale value of the affected vehicles (because Mercedes did not deliver an environmentally compliant car which also met performance expectations) and causing greater environmental damage. The defeat device Mercedes created is different in its details to what Volkswagen has been accused of but the effect (and lawyers say, clearly the intention) was broadly the same.